Biochemical indices and life traits of loggerhead turtles (Caretta caretta) from Cape Verde Islands

The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study.The authors thank the Cape Verde Ministry of Environment (General Direction for the Environment), INDP (National Fisheries Institution), the Canary Islands Government (D.G. Africa and D.G. Research and Universities), ICCM (Canarian Institution for Marine Sciences), the Andalusian Government (Andalusian Environmental Office) and AEGINA PROJECT (INTERREG IIIB) for funding and hosting them during this study. The authors also thank the European Regional Development Fund (ERDF) through the COMPETE - Operational Competitiveness Programme, and national funds through FCT - PEst-C/MAR/LA0015/2011 for supporting the biochemical analysis

Black list and Alert list of the Aquatic Invasive Alien Species in the Iberian Peninsula: an action of the LIFE INVASAQUA

Resumen del trabajo presentado en VI Congreso Nacional sobre Especies Exóticas Invasoras y I Congreso Ibérico sobre EEI (EEI 2022) celebrado en Navarra del 20 al 23 de abril de 2022.One of the objectives of LIFE INVASQUA project is to develop tools that will be more efficient the Early Warning and Rapid Response (EWRR) framework for Invasive Alien Species in the Iberian Peninsula. Horizon scanning for high-risk IAS is basic in implementing measures to reduce new invasions, developing Alert lists, and to focus effort in the species already established, for instance making a Black list. We developed a trans national horizon scanning exercise focused on inland waters of Spain and Portugal in order to provide a prioritized lists (Black list and Alert list) of aquatic IAS that may pose a threat to aquatic ecosystems and socio economic sectors in the future. We followed a step approach of existing information about IAS (Plants, Freshwater Invertebrates, Estuarine Invertebrates and Vertebrates; 127 established taxa in Black list; 90 non established taxa in Alert list) combining with an expert scoring of prioritized taxa. IAS established in the Iberian aquatic system consistently highlighted as the worst included vertebrates (e.g. Cyprinus carpio, Gambusia holbrooki, Silurus glanis), freshwater and estuarine invertebrates (e.g. Procambarus clarkii, Dreissena polymorpha, Pacifastacus leniusculus, Ficopomatus enigmaticus, Callinectes sapidus, Corbicula fluminea) and plants (e.g. Eichhornia crassipes, Azolla filiculoides, Ludwigia grandiflora). Amongst taxa not yet established (Alert list), expert pointed to Perna viridis, Hydroides dirampha, Dreissena bugensis, Procambarus fallax f. virginallis, Perccottus glenii with higher risk of invasion, ecological and socioeconomic impacts. Over 20.6% of the taxa in the preliminary black list received no votes (no prioritization) by experts, 17.8% in the innitial alert list. Our horizon scanning approach is inclusive of all-taxa, prioritizes both established and emerging biological threats across trans-national scales, and considers not only the ecological impact, but also potential direct economic consequences as well as the manageability of invasive species.This work received funds from the LIFE Programme (LIFE17 GIE/ES/000515)

Map of the Cape Verde Archipelago, Boavista Island (Republic of Cape Verde, western Africa) and the study site (framed area).

<p>Map of the Cape Verde Archipelago, Boavista Island (Republic of Cape Verde, western Africa) and the study site (framed area).</p

Relationship between the average condition of hatchlings (standardized RNA/DNA ratio) and the hatching success of the nest they came from (R² = 0.06, p<0.001, F_1,52 = 4.28, p = 0.04).

<p>Relationship between the average condition of hatchlings (standardized RNA/DNA ratio) and the hatching success of the nest they came from (R² = 0.06, p<0.001, F_1,52 = 4.28, p = 0.04).</p

Relationship between the average condition (standardized RNA/DNA ratio) of the hatchlings and their righting time (R² = 0.077, p<0.0001, F_1,52 = 3.923, p<0.0001).

<p>Relationship between the average condition (standardized RNA/DNA ratio) of the hatchlings and their righting time (R² = 0.077, p<0.0001, F_1,52 = 3.923, p<0.0001).</p

Biochemical condition of sea turtles and Hatchling length.

<p>(<b>A</b>). Standardized RNA/DNA ratio (mean ± standard error) for sea turtles in the beginning of the season (Early Season, n = 28) (7^th–12^th of July) and at the end of the season (Late Season, n = 29) (19^th of September–10^th of October); (<b>B</b>). Standardized RNA/DNA ratio (mean ± standard error) for “large” sea turtles (CCL_min>85 cm, n = 26) and for “small” sea turtles (CCL_min≤85 cm, n = 31); (<b>C</b>). Hatchling carapace length (mean ± standard error) for “large” sea turtles (CCL_min>85 cm) and for “small” sea turtles (CCL_min≤85 cm).</p

Standardized RNA/DNA ratio (mean ± standard error) for hatchlings from shaded and unshaded nests.

<p>Standardized RNA/DNA ratio (mean ± standard error) for hatchlings from shaded and unshaded nests.</p

Environmental Markers of Plastics and Microplastics

The slow reaction rates to chemical and photochemical degradation are well-known properties of plastics. However, large plastic surfaces exposed to environmental conditions release particles and compounds that affect ecosystems and human health. The aim of this work was to identify compounds associated with the degradation of polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC) microplastics (markers) on silica and sand and evaluate their use to screen microplastics on natural sand. Products were identified by using targeted and untargeted LC-HRMS analysis. All polymers underwent chemical oxidation on silica. PE released dicarboxylic acids (HO C-(CH ) -CO H ( = 4-30), while PS released / -chalcone, -dypnone, 3-phenylpropiophenone, and dibenzoylmethane. PVC released dicarboxylic acids and aromatic compounds. Upon irradiation, PE was stable while PS released the same compounds as under chemical oxidation but at lower yields. Under the above condition, PVC generated HO C-[CH -CHCl] -CH -CO H and HO C-[CH -CHCl] -CO H ( = 2-19) dicarboxylic acids. The same products were detected on sand but at a lower concentration than on silica due to better retention within the pores. Detection of markers of PE and PS on natural sand allowed us to screen microplastics by following a targeted analysis. Markers of PVC were not detected before or after thermal/photo-oxidation due to the low release of compounds and limitations associated with surface exposure/penetration of radiation

Free Pass Through the Pillars of Hercules? Genetic and Historical Insights Into the Recent Expansion of the Atlantic Blue Crab Callinectes sapidus to the West and the East of the Strait of Gibraltar

The invasive Atlantic blue crab Callinectes sapidus has considerably extended its distribution along the Gulf of Cadiz and Moroccan coasts in the northeast Atlantic. This could indicate a new introduction event in the Gulf of Cadiz from the native area, in case of detectable genetic differences from the Mediterranean Sea populations. To test this and reconstruct the invasion, we assessed the genetic structure of crabs in the Gulf of Cadiz and Alboran Sea. We used sequences of the mitochondrial gene cytochrome c oxidase subunit I (COI), in almost its full length (1511 basepairs), of 149 individuals from three sites along the Spanish Mediterranean coast, two in the Alboran Sea, and two in the Gulf of Cadiz. Our data reveal low genetic variability, with only two haplotypes (here referred to as CSWM1 and CSWM2), compared to its known high genetic diversity in the native range, indicating a strong founder effect in the study region. Here we document an inversion of haplotype predominance between regions, haplotype CSWM2 being dominant in most of the Spanish Mediterranean coast, but less frequent in the Gulf of Cadiz and Alboran Sea. This suggests a secondary introduction of propagules into the investigated area, rather than a new introduction from the native area, nor a natural westward expansion with environmental selection of one haplotype over the other. Further studies with additional populations would help to better unveil the history of yet another invasive species in the Gulf of Cadiz.This study received Portuguese national funds from FCT - Foundation for Science and Technology through projects UIDB/04326/2020, UIDP/04326/2020 and LA/P/0101/2020. This study also received partial financial support from the ATLAZUL (Poctep/Interreg 0755_ATLAZUL_6_E) and ALFCORAZUL projects (Fundo Ambiental, candidature n° 48). JE has a Ph.D. scholarship (SFRH/BD/140556/2018) funded by FCT, Portugal.Peer reviewe